Many diets, including Atkins and the keto diet, fit into this umbrella. A typical low-carb diet limits carbs to less than 60 g daily, but this can vary, according to the Mayo Clinic. (15) In a September 2015 review published in PLoS One, people following low-carb diets saw modest weight loss — although study authors note that long-term effects of the diet require further research. (16)

If you’ve been eating fast food for years, get real about your approach: You’re probably not going to stick to an organic, gluten-free, paleo overhaul for very long. "You want to change as little as possible to create calorie deficit," says Dr. Seltzer, who insists the best way to support sustainable weight loss is to incorporate small changes into existing habits. So instead of giving up your daily BLT bagels in favor of an egg-white wrap, try ordering your sandwich on a lighter English muffin. Or say you eat a snack bar every afternoon: Swap your 300-calorie bar for a 150-calorie alternative. "Your brain will feel the same way about it, so you won’t feel deprived," he says.